This invention relates to furnace systems and methods integrating continuous and batch furnace system elements in which parts can be processed in either a continuous or a batch fashion.
Continuous heat treating systems, including carburizing furnace systems, frequently include interconnected sections or chambers for performing the various treatments employed in the heat treating process. For example, in a carburizing process, these various treatments typically include preheating, carburizing, diffusion, equalize cooling and quenching. U.S. Pat. Nos. 3,598,381 and 3,662,996, whose disclosures are incorporated herein by reference, describe apparatus having interconnected furnace stages, generally rectangular in plan view, for heating, carburizing, diffusion and equalize cooling of metal parts at selected temperatures and in different gaseous atmospheres for specified periods of time. In such systems, trays of parts are pushed or pulled by automated mechanisms one after another through each furnace in a continuous sequence, with each furnace accommodating several trays and each tray generally remaining in the same relative position in its line throughout its passage through the system. Each part receives an identical heat treatment. U.S. Pat. No. 4,763,880, whose disclosure is incorporated herein by reference,; discloses another continuous carburizing furnace system, some of whose stages are rotary furnaces which permit flexibility in the ordering of part flow through the system and in the duration of heat-processing of different parts.
Batch furnace chambers typically accommodate a single tray of parts which is manually loaded into, and later removed from, each chamber. Successive stages of batch heat treat systems are typically not interconnected and results may be somewhat less repeatable than those of continuous systems.